Abstract: A vibration test fixture includes a reciprocating slip table carrying an article subjected to vibration and shock testing. The fixture includes low oil pressure hydrostatic linear bearings supporting the slip plate during single-axis linear travel on the bearings. The slip plate is mounted to each bearing by a single-axis guide system of confining the slip plate to reciprocating longitudinal travel on a general planar, two-dimensional bearing surface which supports the load of the slip plate during its travel. The guide system restrains relative movement of the slip plate laterally and vertically with respect to the bearing surface. A film of lubricating oil is supplied to the bearing surface to lubricate the sliding longitudinal travel of the slip plate on the bearings. The film of lubricating oil is also supplied to the lateral and vertical restraint areas of the bearing.

Abstract: A modular test fixture for use in vibration and shock testing of printed circuit cards comprises a plurality of separate generally planar card-mounting plates each having a two-dimensional array of uniformly spaced apart mounting holes within a rectangular rigid outer frame extending around the outer boundary of each plate. Printed circuit cards of varying sizes are affixed to the mounting plate by clamps positioned along opposite edges of each card, with spaced apart fasteners along each clamp being aligned with and fastened to preselected mounting holes on the plate. The individual card-mounting plates, with the circuit cards attached thereto, are stacked together to form a rigid multi-layer fixture sufficient for vibration and shock testing of the circuit cards mounted at different levels within the fixture. The resulting fixture is fastened to an external shaker for imparting shock and vibration loads to the fixture for use in testing the circuit cards for screening and solder joint defects.

Abstract: A vibration test, bearing table apparatus comprising a support block having a surface slideably supporting a test piece-carrying slip plate intended to oscillate along a single predetermined axis at a desired test frequency responsive to shaker head driving of the slip plate is provided, with an improvement comprising means within the locus of sliding engagement including a cooperating shaft and bearing assembly distributively coupling the slip plate and support block together in a manner maintaining the test piece on a single degree of freedom path coincident with the test axis, whereby tendencies of the driving force to impart spurious cross-axis pitch, yaw and roll test piece motion relative to the intended test axis are blocked.